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Central heating system - advice requested

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I have an approximately fifteen year old Glow Worm Hideaway 80B with a F&E cistern in the loft, and have been having problems that I cannot get to the bottom of.

The issue is that heating only turns on if the hot water is turned off and then on again in a certain order (and only if there is cold water to heat in the hot water tank). Otherwise, the boiler switches on and then off again.

I have had two plumbers over - one local and BG - both have said that it is probably a valve issue, and the BG said that my system is blocked with sludge and needs to be power flushed, but really I should replace the whole system despite the boiler working. I have a couple of questions which I would welcome advice on:

1. If the system is completely blocked with sludge, why would it work when the hot water is turned off and on in the manner that I have described?
2. Assuming that it is not blocked, can it be resolved by using a product like Senintel 400 to remove the sludge?
3. If Sentintel 400 is used, does the system need to be drained before people can use the water - e.g. to shower/drink?

I would appreciate any help because I keep getting told different things and really do not want to replace a system unless absolutely necessary!

Thank you,



From what I`ve read that`s a typical BG Powerflush solves all problems response.

And welcome to the forum Borgia.

Ray Stafford

If you called British Gas out to a faulty cooker, they would want to powerflush your central heating.

It the equivalent of going to the doctor and him telling you to drink less, eat healthier and get more exercise, without even seeing you.


Hi thank you for the welcome and the response. Can I allude from your skepticism that proceeding as I have suggested may be worthwhile?


Gas Engineer
We need more info... What controls do you have?

2 port, 3 port, cylinder thermostat, what sort of programmer... Does not sound sludge related, but controls!!

Eric withy

seems you have trouble with the controls on ye system and probably have a pump over problem to
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